The present invention relates to a digital video recording and reproducing apparatus for recording on or reproducing for a recording medium by digitally processing the video signal.
Generally, a video recording and reproducing apparatus modulates both a luminance signal and a chrominance signal separated from the video signal, then records the modulated luminance and chrominance signal on a recording medium. During reproduction a demodulated luminance component is mixed with a demodulated chrominance component after demodulating the modulated luminance and chrominance component from the recording media.
Therefore, in the video recording and reproducing apparatus, the luminance signal and chrominance signal should be accurately separated from the composite video signal to ensure reliable reproduction of the original picture.
The chrominance signal transmitted with the chrominance carrier of the video signal is distributed within the bandwidth of approximately 3.58 MHz.+-.0.5 MHz which is the center frequency of the chrominance carrier, while the luminance signal is distributed up to the frequency band of the chrominance signal according to the moving quantity of the pixels to the video region i.e., the magnitude of the motion signal.
As a result, the chrominance signal can be separated accurately from the video signal by means of a horizontal comb filter, but the luminance signal is separated accurately from the video signal by a vertical comb low pass filter or a temporal comb low pass filter based on whether the video signal is a moving picture or a static picture i.e., based on the moving quantity of the pixel. The video signal can also be separated by utilizing both vertical comb low pass filter and a temporal comb low pass filter.
Therefore, in the video signal recording and reproducing apparatus, the motion signal is used to separate the luminance signal from the video signal in recording, and is used to reconstruct the luminance signal read out from the recording media during reproduction.
U.S. patent application Ser. No. 07/569,029 on the invention entitled "An improved video signal recording system" filed on Aug. 17, 1990, by Samsung Electronics Co., Ltd., describes a technique for processing the video signal by recording the motion signal together with the video signal, and then reproducing it.
In the U.S. patent application Ser. No. 07/569,029, the motion signal is mixed with the chrominance signal and is recorded on the recording media.
Therefore, errors may be contained in the motion signal in reproducing due to the state of the recording media and noise. If the errors are contained in the motion signal, the construction ratio of the high band component to the low band component of the luminance signal is different from the original construction ratio when the luminance signal is reconstructed. As a result, image quality deteriorates.